Robert L. Sautter

Effectiveness of Preanalytic Practices on Contamination and Diagnostic Accuracy of Urine Cultures: a Laboratory Medicine Best Practices Systematic Review and Meta-analysis

SUMMARY Background. Urinary tract infection (UTI) in the United States is the most common bacterial infection, and urine cultures often make up the largest portion of workload for a hospital-based microbiology laboratory. Appropriately managing the factors affecting the preanalytic phase of urine culture contributes significantly to the generation of meaningful culture results that ultimately affect patient diagnosis and management. Urine culture contamination can be reduced with proper techniques for urine collection, preservation, storage, and transport, the major factors affecting the preanalytic phase of urine culture. Objectives. The purposes of this review were to identify and evaluate preanalytic practices associated with urine specimens and to assess their impact on the accuracy of urine culture microbiology. Specific practices included collection methods for men, women, and children; preservation of urine samples in boric acid solutions; and the effect of refrigeration on stored urine. Practice efficacy and effectiveness were measured by two parameters: reduction of urine culture contamination and increased accuracy of patient diagnosis. The CDC Laboratory Medicine Best Practices (LMBP) initiatives systematic review method for assessment of quality improvement (QI) practices was employed. Results were then translated into evidence-based practice guidelines. Search strategy. A search of three electronic bibliographic databases (PubMed, SCOPUS, and CINAHL), as well as hand searching of bibliographies from relevant information sources, for English-language articles published between 1965 and 2014 was conducted. Selection criteria. The search contained the following medical subject headings and key text words: urinary tract infections, UTI, urine/analysis, urine/microbiology, urinalysis, specimen handling, preservation, biological, preservation, boric acid, boric acid/borate, refrigeration, storage, time factors, transportation, transport time, time delay, time factor, timing, urine specimen collection, catheters, indwelling, urinary reservoirs, continent, urinary catheterization, intermittent urethral catheterization, clean voided, midstream, Foley, suprapubic, bacteriological techniques, and microbiological techniques. Main results. Both boric acid and refrigeration adequately preserved urine specimens prior to their processing for up to 24 h. Urine held at room temperature for more than 4 h showed overgrowth of both clinically significant and contaminating microorganisms. The overall strength of this body of evidence, however, was rated as low. For urine specimens collected from women, there was no difference in rates of contamination for midstream urine specimens collected with or without cleansing. The overall strength of this evidence was rated as high. The levels of diagnostic accuracy of midstream urine collection with or without cleansing were similar, although the overall strength of this evidence was rated as low. For urine specimens collected from men, there was a reduction in contamination in favor of midstream clean-catch over first-void specimen collection. The strength of this evidence was rated as high. Only one study compared midstream collection with cleansing to midstream collection without cleansing. Results showed no difference in contamination between the two methods of collection. However, imprecision was due largely to the small event size. The diagnostic accuracy of midstream urine collection from men compared to straight catheterization or suprapubic aspiration was high. However, the overall strength of this body of evidence was rated as low. For urine specimens collected from children and infants, the evidence comparing contamination rates for midstream urine collection with cleansing, midstream collection without cleansing, sterile urine bag collection, and diaper collection pointed to larger reductions in the odds of contamination in favor of midstream collection with cleansing over the other methods of collection. This body of evidence was rated as high. The accuracy of diagnosis of urinary tract infection from midstream clean-catch urine specimens, sterile urine bag specimens, or diaper specimens compared to straight catheterization or suprapubic aspiration was varied. Authors conclusions. No recommendation for or against is made for delayed processing of urine stored at room temperature, refrigerated, or preserved in boric acid. This does not preclude the use of refrigeration or chemical preservatives in clinical practice. It does indicate, however, that more systematic studies evaluating the utility of these measures are needed. If noninvasive collection is being considered for women, midstream collection with cleansing is recommended, but no recommendation for or against is made for midstream collection without cleansing. If noninvasive collection is being considered for men, midstream collection with cleansing is recommended and collection of first-void urine is not recommended. No recommendation for or against is made for collection of midstream urine without cleansing. If noninvasive collection is being considered for children, midstream collection with cleansing is recommended and collection in sterile urine bags, from diapers, or midstream without cleansing is not recommended. Whether midstream collection with cleansing can be routinely used in place of catheterization or suprapubic aspiration is unclear. The data suggest that midstream collection with cleansing is accurate for the diagnosis of urinary tract infections in infants and children and has higher average accuracy than sterile urine bag collection (data for diaper collection were lacking); however, the overall strength of evidence was low, as multivariate modeling could not be performed, and thus no recommendation for or against can be made.

Clostridium difficile colitis: a retrospective study of incidence and severity before and after institution of an alcohol-based hand rub policy.

BACKGROUND Clostridium difficile-associated diarrhea is a leading cause of hospital-acquired diarrhea. We sought to determine whether the institution of a hospital-wide alcohol-based hand rub (ABHR) policy was associated with an increase in the incidence and/or severity of health care facility-onset, health care facility-associated C difficile diarrhea (CDAD). METHODS We used a retrospective chart review analysis to compare incidence rates of CDAD before and after implementation of the ABHR policy. We also compared rates of sepsis, colectomy, and death in patients with CDAD before and after implementation of the ABHR policy. RESULTS The incidence rate of CDAD was 3.98 per 10,000 patient-days after implementation of the ABHR policy, compared with 4.96 per 10,000 patient-days before implementation (P = .0036). The crude mortality rate in patients diagnosed with CDAD was 10.7% after implementation, compared with 13.3% before implementation (P = .275). The rate of sepsis in patients diagnosed with CDAD was 19.6% after implementation, compared with 5.2% before implementation (P < .0001). CONCLUSION Our data provide no evidence of an increased CDAD rate after implementation of an ABHR policy at our institution. The rate of sepsis in patients diagnosed with CDAD did rise, indicating increased severity of illness in patients with C difficile infection.

Comparison of a rapid latex agglutination assay and a fluorescent-antibody technique for the detection of herpes simplex antibody

A total of 202 serum specimens was tested for the presence of herpes simplex virus antibody using a premarket latex agglutination kit (Wampole) and an indirect fluorescent antibody (IFA) technique (electronucleonics). Discrepant results between the two assays were resolved using an Enzyme-linked immunosorbent assay (ELISA) procedure. The overall sensitivity of the latex was 99.2% with a specificity of 98.5%. The latex agglutination test evaluated is a viable alternative to indirect immunofluorescence for the detection of herpes simplex virus antibody in serum samples.

A Two-Site Analytical Evaluation of the BD Viper System With XTR Technology in Nonextracted Mode and Extracted Mode With Seeded Simulated Specimens

The BD ProbeTec CT Qx Amplified DNA Assay and the BD ProbeTec GC Qx Amplified DNA Assay (both BD Diagnostics, Sparks, MD) represent two new assays developed for use with the BD Viper System with XTR Technology (BD Diagnostics). These assays were built on the foundation of the former BD ProbeTec ET assays (BD Diagnostics) and its accompanying instrumentation. The study described below compared the new assay format, Extracted Mode, to the former assay format, Nonextracted Mode, with the primary objective of examining and measuring overall time expenditures and efficiency of operation. An 80— 142-min reduction in “hands-on” total processing time was observed for the Extracted Mode whether testing urines or swabs. The second objective was to assess the accuracy of performance at low simulated analytical loads for the pathogens Chlamydia trachomatis and Neisseria gonorrhoeae. Performance accuracies for simulated positive and negative urine or swab specimens were calculated to be 99.97% for Extracted Mode and 99.76% for Nonextracted Mode.

Prevalence of Hepatitis C Virus Antibody in Patients With Sexually Transmitted Diseases Attending a Harrisburg, PA, STD Clinic

Objective: The prevalence of hepatitis B and hepatitis C in a sexually transmitted disease (STD) clinic population was studied, along with the prevalence of various STD agents, in an attempt to identify possible STD markers for the hepatitis C virus and help delineate the role of hepatitis C as an STD. The hepatitis C antibody rates found in the STD clinic were also compared with those found among patients attending a local OB/GYN clinic and those enrolled in a blood donor program, all from the same geographical area. Methods: A total of 150 women attending an STD clinc were examined for each of the following agents: Chlamyadia trachomatis, Neisseria gonorrhoeae, syphilis, hepatitis B surface antigen, hepatitis B core antibody, hepatitis B surface antibody, and hepatitis C virus antibody. Additionally, several patients who signed informed consent to be evaluated for human immunodeficiency virus (HIV) antibody were tested by an enzyme immunoassay (EIA) screen method. The prevalence of each agent was then compared with the other agents. Results: The overall prevalence rates detected were as follows: hepatitis B 16%, hepatitis C 4%, chlamydia 18.7%, gonorrhea 7.4%, syphilis 0.7%, and HIV 0%. Hepatitis C antibody was detected in 4% of patients in the STD clinic, 0.76% of volunteer blood donors from central Pennsylvania, and 0% of patiants studied from the Harrisburg Hospital (Harrisburg, PA) prentatal population. Conclusions: This screening study reveals an association between attending a Harrisburg, PA, area STD clinic and having an increased prevalence of hepatitis C antibody, but larger matched control studies will be needed to help clarify sexual transmission as a mode of transmission for the hepatitis C virus.

Evaluation of latex agglutination and dot immunobinding assay for the detection of cytomegalovirus antibody

The Virogen CMV Antibody Test and Difco CMV-Cube were compared with three other available methods, enzyme immunoassay, immunofluorescence and latex agglutination, for the detection of cytomegalovirus (CMV) antibody in 126 random sera submitted to the clinical laboratory. Based on concordance of three or more methods, 72% of the samples were positive for CMV antibody. The sensitivities and specificities of the assays were Virogen, 98% and 97%, and CMV-Cube 97% and 97%, respectively.

Multidisciplinary Team to Achieve Low Blood Culture Contamination Rates in Health Care Facilities

and notification by EMS prior to arrival. When a field is selected, it goes to a drop-down box in the next column to choose specific information and so on through a total of 4 drop-down boxes. There are also “other” choices at the bottom of each column to allow additional data to be free texted. It has been a daunting task to include all potential fields for documentation for a trauma patient. A level II trauma center and I will be testing the new product soon and hope to report success with using only the EMR for documentation in providing a complete record and improving patient safety and outcomes. We will continue to monitor the accuracy of chart documentation and improved continuation of care and look forward to sharing the results.—Ann Quinlan, BSN, RN, Director, Emergency Services, Lake Granbury Medical Center, Granbury, TX; E-mail: Annquinlan1@gmail.com